PIC16F1936 Timers

[Daniel Cioba]

Hi , how can i use timer 4/6 and their interrupts ? It doesn't seems to be implemented in GCB . In file timer.h i could add this timers but i don't know how to add interrupts

[William Roth]

Hi Daniel,

As I read the help file under Timers/Timer Overview there are functions for timer0 through timer5.

As far as interrupts go you can refer to the help file under Interrupts/ON Interrupt and see that Timer0 = Timer5 are supported.

What PIC are you using ?

[Daniel Cioba]

I use PIC16F1936 as in my post title. It has Timer0 , 1 , 2 , 4 and 6. Only Timer0 , 1 and 2 are implemented for PIC microcontrollers in GCB. For the rest you must use manual register settings. I figured out from help file how to use Timer4 / 6 interrupts by creating a subrutine called "interrupts" for all interrupts and manually checking interrupts flags .
So my problem is solved for now ... but it would be nice to improve GCB by adding all available timers and interrupts

[Anobium]

Hi, what release of GCB are your using? The date of the timer.h would also be useful.

Thank you.

Anobium

[Daniel Cioba]

Hi , i use last GCB stable release ,i think, that i downloaded from official site http://gcbasic.sourceforge.net/ Intermediate and Advanced GCB@Syn.zip 25/05/2014
All files including timer.h are from that release , i didn't used GCB before

[William Roth]

I modified the example code code in the help file to use PIC16F1936, timer4, and interrupt on timer4 overflow. It compiles fine. HOwever I don have the Chip to test. Here is the code. I am using Timer.h from the code repository dated 2014-08-23.

~~~~~

chip 16F1936, 8

config osc = int

define MOTOR PORTB.0

'Call the initialisation routine
InitMotorControl

'Main routine
Do
'Increase speed to full over 2.5 seconds
For Speed = 0 to 100
MotorSpeed = Speed
Wait 25 ms
Next
'Hold speed
Wait 1 s
'Decrease speed to zero over 2.5 seconds
For Speed = 100 to 0
MotorSpeed = Speed
Wait 25 ms
Next
'Hold speed
Wait 1 s
Loop

'Setup routine
Sub InitMotorControl
'Clear variables
MotorSpeed = 0
PWMCounter = 0

'Add a handler for the interrupt
On Interrupt Timer4Overflow Call PWMHandler

'Set up the timer
InitTimer4 Osc, PS0_2
'Timer 0 starts automatically on a PIC

End Sub

'PWM sub
'This will be called when Timer 4 overflows
Sub PWMHandler
If MotorSpeed > PWMCounter Then
Set MOTOR On
Else
Set MOTOR Off
End If
PWMCounter += 1
If PWMCounter = 100 Then PWMCounter = 0
End Sub
~~~~~~

[Daniel Cioba]

Sorry , i made a mistake , Timer4 is working fine , only Timer6 is not
Compiler error at InitTimer6 ... and On Interrupt Timer6Overflow ...

Other question , timers2/4/6 all have a prescaler and a postscaler , it is possible to set the postscaler value ? InitTimer0 source, prescaler

[Anobium]

I have just updated Timer.h. I have asked Hugh to complete a code review. I will post when completed.

Revised file now additionally supports:

InitTimer4
InitTimer6
Starttimer (4|6)
Stoptimer (4|6)
Cleartimer (4|6)
Stoptimer (4|6)
and, 
Timer 4 prescales
#define PS4_1/1 0
#define PS4_1/4 1
#define PS4_1/16 2
#define PS4_1/64 3
#define PS4_1 0
#define PS4_4 1
#define PS4_16 2
#define PS4_64 3
and,
'Timer 6 prescales
#define PS6_1/1 0
#define PS6_1/4 1
#define PS6_1/16 2
#define PS6_1/64 3
#define PS6_1 0
#define PS6_4 1
#define PS6_16 2
#define PS6_64 3

Anobium

[William Roth]

So the problem is restricted to timer6?

Looking at Timer.h, it seems that timer6 is not implemented. Also according to the 16F1936.dat file, only "On Interrupt timer6match is supported."

[William Roth]

Anobium is on top of it.

What about the 16F1936 dat file [Interrupt] that does not support timer6 overflow? There will still be a syntax error if this is not remedied.

[Anobium]

@William. On Interrupt Timer6Overflow Call {method} will not compile, but, of course On Interrupt Timer6Match Call {method} will. Constraints of the chip can be removed. :-)

[Anobium]

@All. I have just posted an updated timer.h.

Please see https://sourceforge.net/p/gcbasic/code/HEAD/tree/GCBASIC/trunk/include/lowlevel/timer.h

This will be part of the next release of GCB and GCGB.

[Anobium]

This has all the normal commands for timers, plus the following scalers.

~~~~~
Timer 4 prescales
PS4_1/1
PS4_1/4
PS4_1/16
PS4_1/64
PS4_1
PS4_4
PS4_16
PS4_64

Timer 6 prescales
PS6_1/1
PS6_1/4
PS6_1/16
PS6_1/64
PS6_1
PS6_4
PS6_16
PS6_64